15 March 2020
Beyond the energy market, AGROinLOG has also explored the production of other bio-commodities based pure herbaceous pellets (wheat straw pellets and maize stalk pellets). In the framework of the Spanish demo site, we explored the production of innovative biocomposites boards, thermoplastics reinforced with natural fibres, adsorbent for hydrocarbons and activated carbon for supercapacitors.
The results, described hereafter, are very promising, demonstrating the huge potential of agro-residues as alternative raw materials for new applications.
- Innovative bio-composites boards: Their characteristics of the new boards are within the suitable range for bioboards but a little bit worse than the current material used (sawdust), so no relevant
advantages were achieved. Another constraint is that the purchasing price offered to the supplier (31.5 €/tw.) was very far from the production costs of these pure herbaceous pellets (70-90 €/t).
- Thermoplastics reinforced with natural fibres: The pure herbaceous pellets (100 % wheat straw pellet (WSP-100) and 100 % maize stalk pellet (MSP-100)) are easily processable by injection with Polypropylene; however the injection process is degraded by the temperature and time in the screw, which may affect the final properties. The bending mechanical tests revealed that the wheat-derived materials support more strength than the materials with corn, while in the tensile mechanical tests no significant differences were observed. Polypropylene with 20 wt. % wheat fibre was found to be the most suitable material due to its capability to integrate a higher amount of wheat fibre. The market outlook revealed thermoplastics reinforced with natural fibres as promising materials for future applications in many industrial sectors, especially in the automotive sector
- Adsorbent for hydrocarbons: Both herbaceous materials show promising results as adsorbent for oil. Corn samples showed higher mass adsorbency values than wheat samples, but no significant differences were found. The advantages of these new adsorbents when compared with commercial adsorbents are: lower production costs, similar adsorbency properties and the fact that they are 100 % natural products. By contrast, they present greater volumes and a very careful handling is required to avoid risky situations.
Activated carbon for supercapacitors: Highly microporous materials were obtained from agro-waste biomass with very good electrochemical properties as supercapacitors. Best results at the conditions evaluated were found for the corn-derived biomass prepared by slow pyrolysis and CO2 activation at 800 °C.